John swainson



UNITED sTATEs PATENT oEEroE.

JOHN SWAINSON, OF'NEW- YORK, N. Y.

METALLIC PISTON FOR STEAMENGINES, PUMPS, &C.

specification of Letters Patent No. 159, dated March so, 18s-7.

To all whom it may/concern: t Be it known that I, JOHN SwAINsoN, or

the city, county,'and State of New York,

have invented a new anduseful improvement, never before known, in theconstruction of metallic pistons for steam-engines, cylinders, air-pumpsof condensing-engines, and for the lifting and forcing pumps ofcondensing steam-engines.

The nature of my invention consists in causing the steam, or otherfluid, to act with equal pressure on the whole 4inner surface of thepacking of the piston and to press out the packing with a. force equalto the pressure of the steam or other fluid.

To enable engineers, or others skilled in the art, to make and use myinvention I will proceed to describe its construction and operation.

A view of the piston is seen in the annexed drawing at A. It isconstructed with one plate, cast solid in the middle of the head,dividing the packing into two breadths or apartments.. The top andbottom plates (C and D) are iitted with screens or bolts (E) to hold theplates in their proper places. The top and bottom plates have openingscut in them (see F F, Snc.) to admit the steam or other fluid behind thepacking, so that one breadth of the packing shall be pressed at eachreturn of the stroke.

n The packing consists of metallic rings, cut in segments, (shown at GrGr, &c.) made in two thicknesses-an outer, and an inner one. The innerring, (out into segments) is in one breadth, and the outer thicknessconsists of two rings, (each cut in segments) and arranged soV as tobreak joints. The packing so used can be made of any metal, but IFirstly, the middle plate in the piston head above described, andsecondly, the

f combination therewith of the two outer plates, which contain openings,through .Y

which the steam, or other fluid, can pass in behind the whole innersurface of the packing, and press it out against the cylinder, with a.force equal to the pressure of the steam, or other fluid.

JOHN Sl/VAINSON.

Signed in presence of- OWEN G. WARREN,

L. T. WARREN.

